1. Field of the Invention
The present invention relates to a mobile communication device and a related antenna structure and, more particularly, to a mobile communication device with low near-field radiation and a related antenna structure.
2. Description of the Related Art
With the development of wireless communication technology, the wireless communication products are increasingly ubiquitous. Mobile communication devices, especially the mobile phone, are inextricably linked to people's lives today. In the performance of current mobile phone antennas, the antenna's operating bandwidth and its far-field radiation efficiency are considered. The near-field E-field and H-field strengths of the antenna also recently become important design considerations for practical applications.
The Federal Communications Commission (FCC) stipulates that mobile phones sold in the US must meet the standard of hearing aid compatibility (HAC). That standard is used for restricting the near-field E-field and H-field strengths of the mobile phone antenna in order to prevent the interference of the mobile phone antenna to a user wearing a hearing aid during operation of the mobile phone. According to the standard, the strengths of the near-field E-field and H-field must be restricted under the different operating bands of the mobile phone antenna.
In general, with a bar-type mobile phone, the restriction of the near-field E-field and H-field strengths to the low frequency bands of GSM850/900 (824˜960 MHz) is less stringent, and the high frequency band of UMTS (1920˜2170 MHz) is used at a lower maximum output power (about 0.125 W). Therefore, the three operating bands abovementioned can meet the requirements of the HAC standard. Unlike the abovementioned three operating bands, the high frequency bands of GSM1800/1900 (1710˜1990 MHz) cannot meet the requirements of the HAC standard. In the mobile phone antenna in the prior art, the near-field E-field and H-field strengths cannot be reduced by adjusting the antenna structure. Therefore, the mobile phone antenna in the prior art cannot be considered as an HAC mobile device, because it does not meet the standard of hearing aid compatibility.
Therefore, it is desirable to provide a mobile communication device with low near-field radiation and a related antenna structure to mitigate and/or obviate the aforementioned problems.